Ok maybe this will help.
Proportion = amount of motor speed as compared to pitch at a given setting.
Gain = amount of sensitivity the gyro has to tail rotation not induced by stick position.

Turn the gain down below half setting. Set the heli on a slick surface. (tile floor, concrete floor, kids trampoline) the latter works great beause it is waist high. LOL Now you need to set the proportion first and the gain second. Do a normal power up on the transmitter and heli. Tx first then batt on heli. Set on slick surface and bring heli up to speed trim centered. Get it light on the skids is all. NOW does the heli spin one way or the other. If it does you need to adjust the proportion control. If the nose goes to the right you need to turn the proportion to the right (up) until it stops. Turn it down it the nose goes to the left. NOTICE you need to pay attention to the nose not the tail. Now if you make a change in the proportion control you have to unplug the battery and let the 4 in 1 reset each time you make a change. NO EXCEPTIONS! Now once you get this set you are ready to set the gain control. Starting at about 50% or less pick the heli up in a hover and set the trim again to hold the heli straight. The gyro should be holding the tail fairly straight now if you have it trimmed as close as possible and the tail is still moving you may need a little more gain. The rule for the gain is if you turn it up too far then the tail will start wagging back and forth real fast (twitchy like). If the heli starts doing this then you need to back the gain off a tad bit. Be sure and reset the 4 in 1 each time you make a change in the gyro gain. Maybe this will help you. Give it a try and Always have fun. Gittle